Fitting steps

i have a question about curve fitting.
i created Tgraph object and then i executed the fitting procedure:
i suppose that this procedure works utilising the minimization of chi square. i want to know what the maximum number of steps is.
i would appreciate a reply.

The default fitter being TMinuit (with a singleton gMinuit),

gMinuit->fNfcn is the number of calls to the objective function
gMinuit->fNfcnmx is the maximum number of calls (default is 5000)